1. Field of the Invention
This invention relates to integrated circuit packaging technology, and more particularly, to a method of fabricating a TFBGA (Thin and Fine Ball-Grid Array) package with embedded heat spreader.
2. Description of Related Art
BGA (Ball-Grid Array) is an advanced type of integrated circuit packaging technology which is characterized in the package configuration of a two-dimensional array of solder balls on the bottom surface of the substrate where the semiconductor chip is mounted. These solder balls allow the entire package body to be mechanically bonded and electrically coupled to a printed circuit board (PCB).
TFBGA (Thin and Fine Ball-Grid Array) is a downsized type of BGA technology that provides integrated circuit packages in very small sizes, which are customarily fabricated in batch from a single chip carrier, such as a substrate, predefined with a matrix of package sites, from each of which a single TFBGA package unit is fabricated. Conventionally, however, it would be highly difficult to incorporate an embedded heat spreader in each individual TFBGA package since each individual TFBGA package is quite small in size, typically from 5 mmxc3x975 mm to 15 mmxc3x9715 mm (millimeter), and the specification between neighboring package sites on the substrate is only from 0.2 mm to 0.3 mm.
Related patents include, for example, the U.S. Pat. No. 5,977,626 entitled xe2x80x9cTHERMALLY AND ELECTRICALLY ENHANCED PBGA PACKAGExe2x80x9d, THE U.S. Pat. No. 5,216,278 entitled xe2x80x9cSEMICONDUCTOR DEVICE HAVING A PAD ARRAY CARRIER PACKAGExe2x80x9d, AND THE U.S. Pat. No. 5,776,798 entitled xe2x80x9cSEMICONDUCTOR PACKAGE AND METHOD THEREOFxe2x80x9d, to name just a few.
The U.S. Pat. No. 5,977,626 teaches the embedding of a heat spreader in a BGA package, while the U.S. Pat. No. 5,216,278 teaches the mounting of a heat spreader over the semiconductor chip to facilitate heat dissipation from the encapsulated chip. The U.S. Pat. No. 5,776,798 teaches a novel TFBGA package structure and fabrication thereof. However, none of these patented technologies teach the embedding of a heat spreader in each TFBGA package. Therefore, there still exists a need in the semiconductor industry for a new integrated circuit packaging technology that can incorporate a heat spreader in a TFBGA package.
It is therefore an objective of this invention to provide a new integrated circuit packaging technology that can provide each TFBGA package with an embedded heat spreader to facilitate heat dissipation from the encapsulation chip. In accordance with the foregoing and other objectives, the invention proposes a new method for fabricating a TFBGA package with embedded heat spreader. Broadly defined, the method of the invention comprises the following procedural steps: (1) preparing a substrate having a front surface and a back surface, and which is predefined with a plurality of package sites; (2) preparing a heat-spreader frame including an integrally-formed matrix of heat spreaders having a front surface and a back surface, each heat spreader corresponding to one of the predefined package sites on the substrate; (3) bonding and electrically-coupling a plurality of semiconductor chips to respective package sites on the front surface of the substrate; (4) assembling the heat-spreader frame to the substrate in such a manner that each heat spreader is positioned proximate to one of the semiconductor chips on the substrate (5) performing an encapsulation process to form an encapsulation body which encapsulates the semiconductor chips and the heat-spreader frame; (6) performing a ball-implantation process to implant a plurality of solder balls on the back surface of the substrate; and (7) singulating through the encapsulation body to cut apart the plurality of package sites on the substrate into individual package units, each serving as the intended integrated circuit package.
The foregoing method of the invention is characterized in the use of the heat-spreader frame including an integrally-formed matrix of heat spreaders. Since the entire heat-spreader frame is relatively large in size as compared to the size of an individual TFBGA package, it would be as a whole significantly easier to handle during the fabrication process than a single piece of heat spreader, making embedding of a single piece of heat spreader in each TFBGA package easy to implement.